From: Paolo Bonzini <pbonzini@redhat.com>
To: Wen Congyang <ghostwcy@gmail.com>,
Wen Congyang <wency@cn.fujitsu.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] rcu: actually register threads that have RCU read-side critical sections
Date: Thu, 23 Jul 2015 18:58:14 +0200 [thread overview]
Message-ID: <55B11D26.10402@redhat.com> (raw)
In-Reply-To: <55B0E522.1000009@gmail.com>
On 23/07/2015 14:59, Wen Congyang wrote:
>>>
>>> If the thread doesn't use RCU, rcu_register_thread() is harmless, is
>>> it right?
>>
>> Every rcu_register_thread() makes synchronize_rcu() a little slower.
>
> Yes, but synchronize_rcu() is very slow...
Hmm, worse, rcu_register_thread() if called together with
synchronize_rcu() it waits for the synchronize_rcu() to finish. :/
Paolo
>>
>>>>> be simpler to add an assertion in rcu_register_thread. I'm just a bit
>>>>> wary of doing little more than the bare minimum in 2.4, because of the
>>>>> OS X failure that I didn't quite understand.
>>> Which problem? I don't find it in the maillist.
>>
>> http://article.gmane.org/gmane.comp.emulators.qemu/351548
>
> Hmm, I guess rcu_reader is invalid when pthread key is destroyed.
> pthread key and __thread
> variable, which is destroyed first? I don't find any document to
> describe it.
next prev parent reply other threads:[~2015-07-23 16:58 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-22 14:18 [Qemu-devel] [PATCH] rcu: actually register threads that have RCU read-side critical sections Paolo Bonzini
2015-07-23 2:56 ` Wen Congyang
2015-07-23 5:35 ` Paolo Bonzini
2015-07-23 10:30 ` Christian Borntraeger
2015-07-23 10:42 ` Paolo Bonzini
2015-07-23 11:04 ` Wen Congyang
2015-07-23 11:08 ` Paolo Bonzini
2015-07-23 12:59 ` Wen Congyang
2015-07-23 16:58 ` Paolo Bonzini [this message]
2015-07-24 3:55 ` Wen Congyang
2015-07-24 5:56 ` Wen Congyang
2015-07-24 6:22 ` Paolo Bonzini
2015-07-24 6:30 ` Wen Congyang
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